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Nash–Sutcliffe efficiency can be used to quantitatively describe the accuracy of model outputs other than discharge. This indicator can be used to describe the predictive accuracy of other models as long as there is observed data to compare the model results to.
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. A PSH system stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation.
Field testing of turbines is used to validate the manufacturer's efficiency guarantee. Detailed calculation of the efficiency of a hydropower turbine accounts for the head lost due to flow friction in the power canal or penstock, rise in tailwater level due to flow, the location of the station and effect of varying gravity, the air temperature ...
The Betz limit has no relevance when calculating turbine efficiency in a mobile application such as a wind-powered vehicle, as here the efficiency could theoretically approach 100% minus blade losses if the fluid flow through the turbine disc (or equivalent) were only retarded imperceptibly. As this would require an infinitely large structure ...
A typical hydroelectric plant's operators can bring it from a stopped condition to full power in just a few minutes. Wind farms are variable, due to the natural variability of the wind. For a wind farm, the capacity factor is determined by the availability of wind, the swept area of the turbine and the size of the generator .
The levelized cost of electricity (LCOE) is a metric that attempts to compare the costs of different methods of electricity generation consistently. Though LCOE is often presented as the minimum constant price at which electricity must be sold to break even over the lifetime of the project, such a cost analysis requires assumptions about the value of various non-financial costs (environmental ...
To express the efficiency of a generator or power plant as a percentage, invert the value if dimensionless notation or same unit are used. For example: A heat rate value of 5 gives an efficiency factor of 20%. A heat rate value of 2 kWh/kWh gives an efficiency factor of 50%. A heat rate value of 4 MJ/MJ gives an efficiency factor of 25%.
A wheel power divided by the initial jet power, is the turbine efficiency, η = 4u(V i − u)/V i 2. It is zero for u = 0 and for u = V i. As the equations indicate, when a real Pelton wheel is working close to maximum efficiency, the fluid flows off the wheel with very little residual velocity. [11]